FIRST INSTALLMENT :
High Definition usually refers to 720 horizontal lines of video format resolution or more, but there are a lot of subtle nuances to master before evangelizing the world of “streaming HD Quality” video to the desktop.
I thought I understood the standards and had the answers, so I turned to my good friend WIKIPEDIA for confirmation and all I found was more confusion – click screenshot thumbnail to enlarge, and see how confused the wiki of the world is when it comes to HD!!
First, this is what I thought I knew about 1080i and 1080p – both are HD standards and they both output 1,080 lines of “visual information” at the same time on a wide screen with an aspect ratio of 16:9 – sort of like your computer screen outputting a resolution of 1,920-by-1,080 where that second number 1,080 is the ‘height’ in pixels ( top to bottom) rather than scan lines from top-to-bottom as you would see on a TV.
If that’s true than a resolution of 1,280-by-720 on my PC would be equivalent to a 720P HD signal, correct?
The difference between 1,080 lines “i” vs. “p” –> The “i” stands for “interlaced” while the “p” stands for “progressive”.
Interlaced scan means that the 1,080 lines are split into two sets of lines, the first 540 being “drawn” on a frame, followed by the second 540 drawn on the next frame and they flicker back and forth so quickly, like an old fashioned flip book, that you can’t see the interlace.
This method assists with decreasing the bandwidth and plays back at a frame rate of 50-60fps.
1080P draws the 1,080 lines at the same time at 60 frames per second using more bandwidth at 60 fps.
SECOND INSTALLMENT:: WHAT MY DESKTOP TELLS ME
According to the display properties on my desktop – my max resolution is 1680 x 1050, so according to the standards on the wiki, as long as the video is a minimum of 720 pixels high – and as long as we are suspending disbelief here, we can say that 720 pixels = 720 scan lines and we can “fit” a HD on-line video into that space, we can call it HD.
My screen resolution:
On-line video distributors such as Brightcove are selling video as HD and yet, it falls short in quality.
I wonder how anyone can call this video HD? Maybe the source was HD, but the compression is just not good.
Brightcove calls their Dynamic Player the HD answer – of course as I write this, I am unable to load any videos that are distributed by Brightcove from my 1Gbs internet connection, thusly I am unable to include a screenshot at the moment, I will have to revisit this on Monday – however the video that loaded earlier today still looked pretty bad — to follow is the screen shot I grabbed earlier today, click it and see the artifacts 🙂 